This invention relates generally to the forming of concrete columns, and more particularly, pertains to the specialized treatment of a paperboard tube for use as a form in the pouring of concrete columns.
Various prior art disclosures reveal the use of paperboard tubes for functioning as forms for the forming of concrete, and more specifically, such forms had attained early use for this purpose as an inexpensive means for a disposable building component for use in the building trade. But, as can be readily understood, the use of wound paper tubes as concrete forms subjects the tube to an exposure of an abundance of moisture, as for example, when the poured concrete begins to set in a manner that urges its retained water to transfer either to the top or outwardly to the sides of the column form. As a result, paper tubes have heretofore not been very resistant against deterioration and decay when exposed to such excessive moisture conditions, which usually causes their delamination, and in certain cases, actual failure in supporting the heavy poured concrete.
To overcome such problems, early inventors gave consideration to the treatment of the paperboard tube for the purpose of achieving some sealing, or perhaps provide a moisture barrier lining of the tube component from direct exposure to the fresh concrete. For example, in the United States patent to Atkinson, U.S. Pat. No. 2,316,752, there is disclosed the treatment of surfaces of wooden forms, which also is intended to embrace paperboard type forms, with a surface treatment of a nitrocellulose, such as dipping the form into the lacquer solution. While the principle involved in this Atkinson patent is encouraging from the standpoint of providing some resistance, particularly in the case where a paperboard tube may be involved, as against exposure to moisture, the type of lacquer described in this patent during usage exhibits a very hard resinous interior surface for the form, and which surface could be easily damaged by the aggregate in the concrete, rendering the form very acceptable to on-site damage as by puncturing. The current invention has taken into consideration the type of treatment suggested by Atkinson, but that the treatment of paperboard or fiberboard with a nitro-cellulose as suggested in the Atkinson method was found to be in and of itself unsatisfactory in practice.
Other United States patents gave consideration to the use of a barrier against moisture penetration when utilizing paperboard tubes as concrete forms. For example, in a U.S. patent to Copenhaver, U.S. Pat. No. 2,677,165, the U.S. patent to Clarkson, U.S. Pat. No. 2,836,874, and the U.S. patent to Hart, U.S. Pat. No. 2,914,833, there is disclosed the concept of forming a spirally wound tube that includes an inner liner of a polyethylene film, which is primarily used for the purpose of preventing concrete adhesion to the innermost ply of the tube. The purpose of the teachings of these prior art patents was primarily to lend a quick release of the formed concrete from the interior of the paperboard tube column, and not so much from the standpoint of providing a water barrier for the tube itself, but the problem with these prior developments is that after the concrete column had been formed, and set, and the tube then rapidly removed from the column, the polyethylene liner itself at times had to be delicately stripped from the formed column, thereby necessitating an extra step in the process of forming poured concrete columns in this manner.
Other prior art disclosures gave consideration to the moisture proofing of various paper components, such as shown in the U.S. Pat. No. 3,454,207, to Jackson, which discloses a paperboard container useful for holding paints, which has an interior surface treated with a polyvinylidene chloride, for sealing purposes, and then applies a polyurethane coating to the same surface of the container to provide structural reinforcement. Obviously, the treatment of a container or can under Jackson's teachings are somewhat nonanalogous to the invention herein under consideration, but, the concept was at least present in providing some form of a treated interior surface for a container, at least through the use of a polyvinylidene chloride for the purpose of providing a moisture barrier, even though the urethane coating was applied principally for structural purposes, and not for moisture retarding or release functioning.
It is, therefore, in view of the prior art in existence respecting this invention to provide as its principle object a papertube that is particularly designed and contoured, and multi-coated, so as to provide for its fascile and quick usage in forming poured concrete columns.
Another object of this invention is to provide a paperboard tube which is split into particular configurations that facilitate its easy usage and assembly into a form for the constructing of concrete columns.
Another object of this invention is to provide a paperboard tube which is designed cut and coated at particular locations so as to furnish a moisture resistant form for pouring of concrete columns, and also to provide for a quick release of a paperboard tube from the concrete column after its setting.
A further object of this invention is to provide a process for the chemical treating of paperboard tubes, at the plant site, for eventual use in the forming of concrete columns.
Another object of this invention is to provide a particularly designed chemical solution for use in preventing delamination of paperboard tubes when exposed to high moisture conditions.
A further object of this invention is to furnish a quick release of paperboard tubes from concrete when used in forming multi shaped columns.
These and other objects will become more apparent to those skilled in the art upon reviewing the summary of this invention, and upon undertaking a study of the description of the preferred embodiment in view of its drawings.